Personal care products, such as, diapers, sanitary napkins, adult incontinence garments, and the like are generally constructed from a number of different components and materials. Such articles typically have a portion, usually the backing layer, liner, or baffle constructed of a liquid repellent film material. This repellent material is appropriately constructed to minimize or prevent the exudation of the absorbed liquid from the article and to obtain greater utilization of the absorbent capacity of the product. The liquid repellent film commonly used includes plastic materials such as polyethylene films and the like.
Although such products are relatively inexpensive, sanitary and easy to use, disposal of such a product once soiled is not without its problems. With greater interest being placed in protecting the environment today, there is a need to develop materials that are more compatible with the existing and developing waste disposal technologies while still delivering performance consumers have come to expect. An ideal disposal alternative would be to use municipal sewage treatment and private residential septic systems. Products suited for disposal in sewage systems can be flushed down a convenient toilet and are termed "flushable." While flushing such articles would be convenient, the liquid repellent material which normally does not disintegrate in water tends to plug toilets and sewer pipes. It therefore becomes necessary, although undesirable, to separate the barrier film material from the absorbent article prior to flushing.
In addition to the article itself, typically the packaging in which the disposable article is distributed is also made from a water resistant material. Water resistivity is necessary to prevent the degradation of the packaging from environmental conditions and to protect the disposable articles therein. Although this packaging may be safely stored with other refuse for commercial disposal, and especially in the case of individual packaging of the products, it is often more convenient to dispose of the packaging in the toilet with the discarded disposable article. However, in the cases where such packaging is composed of a water resistant material, plugging of the drains to the toilet typically results.
In an effort to overcome these deficiencies, two methodologies have been utilized. The first is for hydrophilic materials to be treated with a hydrophobic material to impart the desired water resistant properties to the material.
The second method has been to modify a water resistant polymer. One of the more useful ways of modifying polymers involves blending them with other polymers of different structures and properties. In a few cases, polymer blend combinations are thermodynamically miscible and exhibit physical and mechanical compatibility. However, by far a greater number of blends are phase separated and generally exhibit poor mechanical compatibility. Phase separated blends can in some cases exhibit physical and mechanical compatibility where the polymer compositions are similar, for example, polyolefin blended with other similar polyolefins, or where interfacial agents are added to improve the compatibility at the interface between the constituents of the polymer blend.
Polymer blends of polyolefins and poly(ethylene oxide) are melt processible but exhibit very poor mechanical compatibility. This poor mechanical compatibility is manifested in the mechanical property profile of the blends relative to the properties of the unblended constituents.
In view of the problems of the prior art, it remains highly desirable to provide a water responsive material. Such blends could be used for making flushable barrier films, extrusion applications and injected molded articles.